Using enhancement boards, Doug Macrae and Kevin Curran, overlaid code onto existing Missile Command arcade machines. The result was a more luridly coloured but also a harder game: accelerated in speed and with a new laser shooting UFO. Atari sued the Macrae and Curran, claiming that they were copying code, but Macrae and Curran were successful in defending their code as a new overlay rather than a copy. Atari dropped the suit, but they also bought off the two coders and hired them to 'enhance' or design games for Atari. Their next 'enhancement' was transforming Pac Man in to Ms. Pac Man, the most popular video game of arcade era.